The SEL-700G Relay is the right solution for utility and industrial generator protection, with an autosynchronizer, flexible I/O, and advanced communications. Apply the SEL-700G Relay for comprehensive primary and backup generator protection.
The SEL-700G provides a complete protection and synchronization solution for synchronous generators. Eliminate the complexity and cost of standalone synchronizer packages. Integrating the synchronization capability into the generator protection relay provides the most cost-effective and reliable solution. Easily upgrade protection without cutting or drilling existing cutouts with a small form factor and multiple mounting adapters. Quickly integrate into serial- or Ethernet-based communications with Modbus, DNP3, IEC 61850, Mirrored Bits communications, and other protocols.
Applications
Comprehensive Generator Protection—Connect the SEL-700G Generator Protection Relay across small, medium, or large generators for complete primary and backup protection. The SEL-700GT provides an IEEE 1547 compliant intertie protection solution for distributed generation. Adding the neutral voltage connection provides 100 percent stator ground protection, based on third-harmonic voltage measurements. Connecting the neutral current input provides protection for solidly grounded or resistance-grounded machines.
Autosynchronizer—Replace external generator control and synchronizer relays with the built-in automatic synchronizer function. Frequency, voltage, and phase control of the generator are automatically synchronized and connected to the power system. Monitor the generator synchronization process using generator start reports and the PC-based synchroscope.
Current Differential Protection—Apply sensitive percentage-restrained current differential elements and an unrestrained element, along with synchronism check and volts-per-hertz elements, across the entire unit to protect both the generator and the step-up transformer. Optional current differential elements detect stator faults using a secure, sensitive current differential function. Power transformer and CT connection compensation allows the unit step-up transformer to be included in the generator differential zone.
Breaker Wear Monitoring—Record accumulated breaker contact wear with the breaker monitor function, which uses the manufacturer’s specifications for defining breaker operation limits. The internal monitor tracks the total number of close/open operations and integrates the interrupted current per phase. Set an alarm to alert operators when measured and accumulated quantities approach maintenance thresholds. This information facilitates proactive breaker maintenance and replacement without underutilizing resources.
Easy Communications—Choose from single or dual ports, copper or fiber-optic Ethernet or serial communications, and several protocols, including Mirrored Bits communications and IEC 61850. Pick multiple Modbus TCP or Modbus serial sessions for custom configuration of your application. Use DNP3 Serial or DNP3 LAN/WAN protocols.
Overview
Comprehensive Generator Protection
Numerous current, voltage, frequency, distance, power, and out-of-step elements provide comprehensive protection for large, medium, and small generators.
Autosynchronizer
The optional, built-in automatic synchronizer function eliminates the need for expensive external synchronizer equipment. Frequency, voltage, and phase control of the generator are automatically synchronized and connected to the power system.
Easy Communications
Choose from single or dual ports, copper or fiber-optic Ethernet or serial communications, and several protocols, including Mirrored Bits communications and IEC 61850. Pick multiple Modbus TCP or Modbus serial sessions for custom configuration of your application. Use DNP3 serial or DNP3 LAN/WAN protocol.
One Hundred Percent Stator Ground Detection
The SEL-700G detects stator ground faults on high-impedance grounded generators using a conventional neutral-overvoltage element with a third-harmonic voltage differential detection scheme for 100 percent stator winding coverage.
Current Differential Protection
Optional current differential elements detect stator faults using a secure, sensitive current differential function. Power transformer and CT connection compensation allows the unit step-up transformer to be included in the generator differential zone.
Power Elements
Sensitive power elements protect against reverse power, overload conditions, or low forward power.
RTD-Based Thermal Protection
Use an internal 10 RTD input card or an external SEL-2600 RTD Module to acquire thermal data for alarm, monitoring, and trip functions in the SEL-700G.
Metering and Reporting
View generator autosynchronizer, Sequential Events Recorder (SER), and 180-cycle oscillographic event reports to analyze generator startup, shutdown, or system faults. Measure electrical, thermal, and generator run-time quantities.
Synchrophasor Data
Apply SEL synchrophasors (IEEE C37.118) to turn state estimation into state measurement and to provide early warning of potential system instability. The SEL-700G phasor measurement accuracy meets the IEEE C37.118-2005 Level 1 requirement.